This is the first release candidate of the 1.3 series. The 1.3 series are
a major improvement with a completely rewritten connection handling backend. It has been
rewritten to form a new improved framework for handling connections. On top of
this new framework, new functionality is also implemented to provide read
preference support that comes with MongoDB 2.2. The new framework no longer has
the concept of a connection pool, but instead make sure there is only one
connect per node/db/username.

New major features in this release to support the MongoDB 2.2 release:

- Support for the aggregation framework through the aggregate() helper.
- Support for read preferences and read preference tags (See:
http://docs.mongodb.org/manual/applications/replication/#replica-set-read-preference)
- Support for connections to multiple mongos nodes.